System and method for integrated biopsy and therapy

ABSTRACT

A system and method for integrating diagnosis and treatment for internal tissues includes imaging at least a portion of an internal organ of a subject using a first technology capable of differentiating tissue types, and targeting and accessing biopsy sites using images of the first technology fused with images of a second technology capable of real-time image updates. Treatment of a biopsy site is planned using the images of the first technology. Instruments for treating the biopsy site are guided by fusing the images of the first technology with the images of the second technology.

This application is a continuation of U.S. application Ser. No.13/321,836, filed Nov. 22, 2011, which is a national stage entry ofPCT/IB2010/052152 filed May 14, 2010 (WO 2010/140075), which claimspriority to provisional application Ser. No. 61/184,322, filed Jun. 5,2009, all incorporated herein by reference.

This invention was made in the performance of a Cooperative Research andDevelopment Agreement with the United States Public Health Service(CRADA No. NCI-NIHCC-01864). The Government of the United States hascertain rights in the invention.

This disclosure relates to imaging technology, and more particularly tosystems and methods that integrate biopsy imaging with therapeuticprocedures.

Prostate cancer affects one in every six men in the western world atsome point in their lives. Because of the lack of imaging and imageguidance, conventional (blind) sextant biopsy used for diagnosis ispainful and unreliable. As a result, prostate cancer is over-diagnosedand over-treated. In therapy, almost all prostate cancers are currentlytreated by surgery or whole-prostate radiation therapy, leading tosignificant side effects.

Today, prostate cancer care is performed without ample visual feedback.A biopsy is ultrasound guided because ultrasound is real-time andcost-effective and can be employed to visualize the prostate.Unfortunately, ultrasound does not show a cancer. So, instead of goingfor the cancer in a targeted, image-guided way, the biopsy is blindlysampled with a sextant biopsy, which results in an up to a 30% falsenegative rate. One problem with image guidance also extends to prostatecancer therapy. Without adequate guidance, therapy approaches remainlimited to whole-gland therapy, which shows significant side effectssuch as urinary incontinence and impotence in a large number ofpatients. Therefore, a move away from blind and whole-gland approachesneeds to be made.

In accordance with the present principles, a move toward targeted,localized procedures is made. Magnetic resonance imaging (MRI) iscurrently the most promising imaging modality for depicting prostatecancer and other abnormalities and cancers on internal organs. Magneticresonance imaging (MRI) guidance is not compatible with currentworkflows, however. Since MRI is expensive and typically not used forprocedure guidance, it is desirable to fuse pre-operative MRI withreal-time transrectal ultrasound (TRUS) during an intervention relatedto the prostate. As a result, the MRI information can be used during theintervention outside the MRI suite. In a previous work, the presentinventors developed an image fusion system for MRI/TRUS guided targetedbiopsy. The fusion system utilized electromagnetic (EM) tracking forspatial localization of an ultrasound probe. Spatial tracking of theprobe is enabled by attaching a biopsy guide to the probe that iscustomized with electromagnetic tracking sensors.

Although MRI has good sensitivity and specificity in prostate cancerdiagnosis, it may not be sufficiently definitive. MRI may missidentifying prostate lesions, suggesting that MRI-targeted prostatebiopsy alone may be insufficient. In accordance with the presentembodiments, a sextant biopsy employs a targeted biopsy to increase theyield of the sextant biopsy and detect lesions that are not recognizableby MRI.

In the current standard care of prostate cancer, prostate biopsy andtherapy are two separate procedures. Therefore, even if lesions arefound in the sextant biopsy procedure, it is difficult to go backexactly to the same location during the therapy to treat the lesion. Theposition information of sextant biopsy is under-utilized. With thetracked biopsy and image fusion, the gap between prostate biopsy andfocal therapy can be bridged by using the same diagnosis MRI image todocument biopsy, plan for therapy and provide image guidance.

An integrated prostate cancer suite in accordance with the presentprinciples enables physicians to seamlessly plan, navigate, execute andmonitor a biopsy or focal therapy procedure. It is based on the fusionof pre-acquired MRI with live transrectal ultrasound (TRUS): targetinformation from MRI augments TRUS guidance, which improves the accuracyof biopsy and focal treatment.

A system and method combine biopsy and therapy by using a samediagnostic MRI image to document biopsy, plan for therapy and provideimage guidance. In one embodiment, the system/method includes thefollowing: (1) performing tracked sextant with MRI-targeted biopsies forprostate cancer detection, (2) identifying all the biopsy sites on MRIusing MRI/TRUS fusion, (3) planning focal therapy on the MRI image usingthe pathology results of the biopsy specimens, and (4) fusing theMRI-based treatment plan with real-time TRUS for focal therapy guidance.Combining sextant biopsy with targeted biopsy increases the yield ofsextant biopsy and detects lesions that are not recognizable by MRI.Prostate biopsy and therapy can be carried out at different times, butthe biopsy findings are used to guide the therapy. The system and methodare adaptable and not limited to treatment of prostate cancer.

A system and method for integrating diagnosis and treatment for internaltissues includes imaging at least a portion of an internal organ of asubject using a first technology capable of differentiating tissuetypes, and targeting and accessing biopsy sites using images of thefirst technology fused with images of a second technology capable ofreal-time image updates. Treatment of a biopsy site is planned using theimages of the first technology. Target information that may be used fortreatment planning includes positive biopsy locations and/or suspiciousregions of diagnostic images (e.g. MRI or MRI+PET fusion). Instrumentsfor treating the biopsy site are guided by fusing the images of thefirst technology with the images of the second technology.

These and other objects, features and advantages of the presentdisclosure will become apparent from the following detailed descriptionof illustrative embodiments thereof, which is to be read in connectionwith the accompanying drawings.

This disclosure will present in detail the following description ofpreferred embodiments with reference to the following figures wherein:

FIG. 1 is a block diagram showing a system and method for integratingdiagnosis and treatment for internal tissues in accordance with thepresent principles;

FIG. 2 is a block/flow diagram showing a system/method for integratingdiagnosis and treatment for internal tissues in accordance with thepresent principles;

FIGS. 3A-3C are MRI images showing three views of a specimen employed inaccordance with an illustrative procedure; and

FIG. 3D is a fused image combining an MRI with and ultrasound image inaccordance with an illustrative embodiment.

The present disclosure describes systems and methods for fusing imagingtechnologies and employing biopsy information in therapy or subsequentprocedures. The present embodiments will be illustratively described interms of prostate cancer diagnosis and therapy. It should be understoodthat the present principles may be employed for other cancers orprocedures and should not be construed as limited by the illustrativeexamples. In one particularly useful application, MRI imaging andMRI/ultrasound fusion technologies are employed to enable lesiontargeted biopsy and focal therapy which may reduce side effects. (E.g.,conventional prostate cancer biopsy and therapy are blind, whole-glandprocedures with significant side effects).

MRI is insufficient to detect all prostate cancer. To improve theoutcome of the procedures, a method in accordance with one embodimentincludes performing a tracked sextant with MRI-targeted biopsies forprostate cancer detection; identifying all the biopsy sites on the MRIusing MRI/TRUS fusion; planning focal therapy on the MRI image using thepathology results of the biopsy specimens and fusing the MRI-basedtreatment plan with real-time TRUS for focal therapy guidance. Thismethod bridges the gap between prostate biopsy and therapy, increasesthe yield of biopsy and reduces the side effects of therapy.

It should be understood that the present disclosure is applicable forany cancer or disease in any organism. The elements depicted in theFIGS. may be implemented in various combinations of hardware and/orsoftware and provide functions which may be combined in a single elementor multiple elements.

Furthermore, the present principles can take the form of a computerprogram product accessible from a computer-usable or computer-readablemedium providing program code for use by or in connection with acomputer or any instruction execution system. A computer-usable orcomputer readable medium can be any apparatus that may include, store,communicate, propagate, or transport the program for use by or inconnection with the instruction execution system, apparatus, or device.The medium can be an electronic, magnetic, optical, electromagnetic,infrared, or semiconductor system (or apparatus or device). Examples ofa computer-readable medium include a semiconductor or solid statememory, magnetic tape, a removable computer diskette, a random accessmemory (RAM), a read-only memory (ROM), a rigid magnetic disk and anoptical disk. Current examples of optical disks include compactdisk-read only memory (CD-ROM), compact disk-read/write (CD-R/W) andDVD.

A data processing system suitable for storing and/or executing programcode may include at least one processor coupled directly or indirectlyto memory elements through a system bus. The processor or processingsystem may be provided with the scope system or provided independentlyof the scope system. The memory elements can include local memoryemployed during actual execution of the program code, bulk storage, andcache memories which provide temporary storage of at least some programcode to reduce the number of times code is retrieved from bulk storageduring execution. Input/output or I/O devices (including but not limitedto keyboards, displays, pointing devices, etc.) may be coupled to thesystem either directly or through intervening I/O controllers.

Network adapters may also be coupled to the system to enable the dataprocessing system to become coupled to other data processing systems orremote printers or storage devices through intervening private or publicnetworks. Modems, cable modem and Ethernet cards are just a few of thecurrently available types of network adapters.

Referring now to the drawings in which like numerals represent the sameor similar elements and initially to FIG. 1, a system 100 is depictedfor combining biopsy information with therapy. System 100 includes atracking system 102 employed during an ultrasound-guided medicalprocedure. The tracking system 102 may include, e.g., an electromagnetictracking system with a field generator placed near a patient or subject107 to provide positional coordinates of a tracking sensor(s) 106 duringa procedure. In one embodiment, the tracking sensor 106 is attached toan ultrasound probe 108. Alternatively, a needle guide 110 may beprovided with tracking sensors 106 which can be attached to theultrasound probe 108. Optionally, the tracking sensor 106 may beattached to a biopsy needle 112. The equipment and methodology may bevaried in accordance with the procedure and anatomy being analyzed andtreated.

A processing unit 116 is connected to the tracking system 102 and anultrasound scanner 118 (or other real-time scanning technology). Theprocessing unit 116 simultaneously obtains ultrasound images from thescanner 118, and corresponding position information from the sensor 106.The processing unit 116 can be a workstation, or may be part of theultrasound scanner 118. The processing unit 116 includes memory 121which includes a software program 120 for execution on the processingunit 116 that guides an MRI-targeted biopsy, acquires and storesreal-time ultrasound images, together with the volume's tracking systemcoordinates provided by the sensor 106, identifies the needle 110 orother interventional device in real-time or recorded ultrasound, andtransforms the biopsy sample's position to a corresponding spot in anMRI image 119. Processing unit 116 includes software 123 for focaltherapy planning based on the MRI image 119, the biopsy positions in theMRI image 119 and pathology results of the biopsies.

An image guidance system 122 executes on processing unit 116 for focaltherapy that permits fusing a treatment plan with real-time ultrasonicimaging, and guiding targeted focal therapy based on the plan.Optionally, the image guidance system 122 of the biopsy can be adaptedfor focal therapy, or the image guidance system 122 for focal therapycan be based on mechanical devices 124 with position encoders andtemplate grids. Such mechanical devices can therefore be accuratelytracked with reference to image positions obtained in real-time andfused with other images (e.g., MRI).

Advantageously, the MRI images and the scanner images (e.g., ultrasonicimages) are combined or fused using device tracking (e.g., theultrasound probe, a registration pointer etc.) and/or imageregistration. Once registered, real-time images (e.g., ultrasoundimages) may benefit from the detailed MRI images (or other type images)since the fused images provide a complete set of information. Theinformation is advantageously employed for both diagnosis and fortreatment, and the fused image can be updated in real-time to trackdiagnosis, analysis and treatment. Scanned and fused images may beviewed using one or more display devices 130, which provide visualfeedback for users to interface with the system 100.

Referring to FIG. 2, a block/flow diagram illustratively depicts asystem/method for diagnosis (e.g., biopsy) and treatment (e.g., focaltherapy) for a surgical procedure. In the present example for prostatecancer, the system/method combines a tracked sextant and MRI-targetedbiopsies for prostate cancer detection. In block 202, images arecollected for a subject. The images preferably employ a technologycapable of differentiating between tissues (e.g., MRI technology). Inblock 204, static (e.g., MRI or other technology) images are fused withreal-time updated images (e.g., ultrasonic images) by performing aregistration method or by employing tracked coordinate systems. In block205, all the biopsy sites are identified on the MRI using MRI/TRUSfusion. The biopsy site(s) is targeted and samples are obtained usingguided interventional instruments in block 206. Positional informationfor the biopsy site(s) is recorded and stored for use later intherapy/treatment.

The MRI image is then used to plan for focal therapy based on apathology examination of the biopsy specimens in block 207. The plan(static image) is fused with real-time images (e.g., TRUS) to guidefocal therapy in block 208. The plan is carried out or executed usingthe MRI and TRUS information in the fused image in block 210.

MRI-targeted biopsy: The prostate MR image is acquired first andtransferred to a workstation (e.g., 116, FIG. 1). The patient is thenpositioned on an examination table and a 2D TRUS probe with trackingsensors is inserted into the rectum. At the beginning of the TRUSprocedure, the operator performs a 2D axial sweep (prostate base toapex) such that the series of 2D ultrasound images covers the entirevolume of the prostate. (In an alternative, a 3D ultrasound probe can beused to obtain the prostate volume.) The images and correspondingtracking data from the tracking sensors are transferred to theworkstation in real-time. Based on these images and tracking data, avolumetric ultrasound image is immediately reconstructed on theworkstation. The MR image and ultrasound volume are then spatiallyaligned. During the procedure, the operator manually holds the 2D probeto scan the prostate. Spatial tracking of the ultrasound probe, andregistering MRI coordinate system with the tracking coordinate system,enables real-time fusion of the live ultrasound image with the spatiallycorresponding multi-planar reconstruction (MPR) from the MRI scan.

When prostate motion results in misalignment between the ultrasound andMR images, image-based registration between the real-time 2D ultrasoundimages and the static ultrasound volume will be carried out to recoverthe correct MRI/TRUS fusion. A tissue sample may be obtained when theneedle is aligned with the target.

Tracked sextant biopsy: Tracked sextant biopsy can be carried out with atargeted biopsy under the same clinical setup. The order between them isnot important. The physician can ignore the MRI image and performsextant biopsy under TRUS guidance only. The TRUS images and thecorresponding tracking information of the probe can be recorded. Thelocations of sextant biopsy can be (retrospectively) identified on theMRI using MRI/TRUS fusion as shown in FIGS. 3A-3D.

Referring to FIGS. 3A-3D, images of a prostate region in a subject areillustratively depicted. FIGS. 3A-3D show the development of an MRI/TRUSfusion for a biopsy needle firing. FIG. 3D shows an alpha-blending ofMRI and TRUS images. This fusion provides the accuracy needed foridentifying particular tissues along with the dynamic and real-timeimages provided by ultrasound. FIGS. 3A-3C show axial, sagittal andcoronal views, respectively, of an MRI focused on a mid-point of aspecimen to be analyzed and treated in a patient. Markers 302, 304 and306 show two end points (302 and 306) and a mid-point (304) of thebiopsy specimen. The markers 302, 304 and 306 indicate a biopsy needletrajectory.

While MRI images are described, instead of using an MRI volume fordiagnosis, procedure guidance and treatment planning, other 3D (or 4D)image volumes may be employed (e.g., computed tomography (CT), positronemission tomography (PET), single photon emission computer tomography(SPECT), 3D ultrasound, and cancer probability mapping, and image fusionof multiple diagnostic images such as MRI, PET and contrast ultrasound,etc.). Further, instead of using electromagnetic tracking, optical,mechanical or other tracking systems may be employed.

After the locations of sextant and targeted biopsies are identified onthe MRI images, the locations can be correlated with the pathologyexamination of the specimens collected during the biopsy. A treatmentplan can be made on the MRI image to cover all the cancer locations andspare the healthy tissue. Both positive and negative biopsy cores can beused to plan focal therapy. In other embodiments, instead of performingseparate sextant and MRI-targeted biopsies, the sites of the sextantbiopsy can be optimized based on the MRI target locations to maximizethe probability for finding cancer. The processes described may beapplied to ultrasound/MR images of the breast, liver, kidney or othersoft-tissue targets.

The workflow of focal therapy is similar to that of the MRI-targetedbiopsy. Instead of using the MRI targets, the treatment plan can behighlighted on real-time TRUS for procedure guidance. The therapymodality can be any modality suitable for focal therapy, such ascryo-ablation, radiofrequency ablation or other ablative therapies,brachytherapy or other radiation-based therapy, or photodynamic therapy.

Advantageously, results from several biopsies—even obtained on differenttimes/dates—can be combined by registering a reconstructed ultrasoundvolume obtained for each biopsy with the same baseline MRI scan, or byregistering the ultrasound sweeps with different MRI scans which in turnare spatially co-registered. The treatment delivery locations can betracked and recorded as well with the same tracking system used to trackbiopsy locations. The system can then also be used for optimizingmultiple, sequential treatments over time, by considering prior treatedregions in the treatment plan for subsequent/repeat treatments (e.g.,avoiding unnecessary duplication of treatment in the same area). In oneembodiment, electronic images may be colorized or otherwise marked toidentify treated regions or regions yet to be treated or both. Othermanipulations of images data are also contemplated.

In interpreting the appended claims, it should be understood that:

a) the word “comprising” does not exclude the presence of other elementsor acts than those listed in a given claim;

b) the word “a” or “an” preceding an element does not exclude thepresence of a plurality of such elements;

c) any reference signs in the claims do not limit their scope;

d) several “means” may be represented by the same item or hardware orsoftware implemented structure or function; and

e) no specific sequence of acts is intended to be required unlessspecifically indicated.

Having described preferred embodiments for systems and methods (whichare intended to be illustrative and not limiting), it is noted thatmodifications and variations can be made by persons skilled in the artin light of the above teachings. It is therefore to be understood thatchanges may be made in the particular embodiments of the disclosuredisclosed which are within the scope and spirit of the embodimentsdisclosed herein as outlined by the appended claims. Having thusdescribed the details and particularity required by the patent laws,what is claimed and desired protected by Letters Patent is set forth inthe appended claims.

1. A method for integrating diagnosis and treatment for internaltissues, comprising: imaging at least a portion of an internal organ ofa subject using a first technology capable of differentiating tissuetypes; targeting and accessing biopsy sites using images of the firsttechnology fused with images of a second technology capable of real-timeimage updates; planning treatment of at least one of the biopsy sitesusing the images of the first technology; and guiding instruments fortreating the at least one biopsy site by fusing the images of the firsttechnology with the images of the second technology.